<?php
/**
 * Memcached storage engine for cache
 *
 *
 * PHP 5
 *
 * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
 * Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
 *
 * Licensed under The MIT License
 * For full copyright and license information, please see the LICENSE.txt
 * Redistributions of files must retain the above copyright notice.
 *
 * @copyright     Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
 * @link          http://cakephp.org CakePHP(tm) Project
 * @package       Cake.Cache.Engine
 * @since         CakePHP(tm) v 1.2.0.4933
 * @license       http://www.opensource.org/licenses/mit-license.php MIT License
 */

/**
 * Memcached storage engine for cache. Memcached has some limitations in the amount of
 * control you have over expire times far in the future. See MemcachedEngine::write() for
 * more information.
 *
 * @package       Cake.Cache.Engine
 */
class MemcachedEngine extends CacheEngine {

/**
 * Contains the compiled group names
 * (prefixed with the global configuration prefix)
 *
 * @var array
 */
	protected $_compiledGroupNames = array();

/**
 * Memcached wrapper.
 *
 * @var Memcached
 */
	protected $_Memcached = null;

/**
 * Settings
 *
 *  - servers = string or array of memcache servers, default => 127.0.0.1. If an
 *    array MemcachedEngine will use them as a pool.
 *  - compress = boolean, default => false
 *
 * @var array
 */
	public $settings = array();

/**
 * Initialize the Cache Engine
 *
 * Called automatically by the cache frontend
 * To reinitialize the settings call Cache::engine('EngineName', [optional] settings = array());
 *
 * @param array $settings array of setting for the engine
 * @return boolean True if the engine has been successfully initialized, false if not
 */
	public function init($settings = array()) {
		if (!class_exists('Memcached')) {
			return false;
		}
		if (!isset($settings['prefix'])) {
			$settings['prefix'] = Inflector::slug(APP_DIR) . '_';
		}
		$settings += array(
			'engine' => 'Memcached',
			'servers' => array(
			    array('10.25.65.177',11211),    // y7
                // array('10.168.245.102',11211), // y3
                array('10.27.9.227',11211), // y8
            ),
			'compress' => false,
			'persistent' => true
		);
		parent::init($settings);

		$this->settings['compress'] = false;
		if (is_string($this->settings['servers'])) {
			$this->settings['servers'] = array($this->settings['servers'],11211);
		}
		if (!isset($this->_Memcached)) {
			$return = false;
			$this->_Memcached = new Memcached();
			
			$this->_Memcached->setOption(Memcached::OPT_BINARY_PROTOCOL, true); //使用binary二进制协议
			// 指定元素key分布到各个服务器的方法  http://php.net/manual/zh/memcached.constants.php
			$this->_Memcached->setOption(Memcached::OPT_CONNECT_TIMEOUT, 500); // 毫秒
            // 自动failover配置。 OPT_AUTO_EJECT_HOSTS不要使用
			//$this->_Memcached->setOption(Memcached::OPT_SERVER_FAILURE_LIMIT, 1);
			//$this->_Memcached->setOption(Memcached::OPT_AUTO_EJECT_HOSTS, true);
			
			$this->_Memcached->setOption(Memcached::OPT_DISTRIBUTION,Memcached::DISTRIBUTION_CONSISTENT);
			$this->_Memcached->setOption(Memcached::OPT_LIBKETAMA_COMPATIBLE,true);
			//最新的libmemcached的文档中可以看到更建议使用如下的选项. #https://yq.aliyun.com/articles/27391
			$this->_Memcached->setOption(Memcached::OPT_REMOVE_FAILED_SERVERS,true);

            return $this->_Memcached->addServers( $this->settings['servers'] );
//			foreach ($this->settings['servers'] as $server) {
//				list($host, $port) = $this->_parseServerString($server);
//                if ($this->_Memcached->addServer($host, $port)) {
//                    $return = true;
//                }
//			}
//			return $return;
		}
		return true;
	}

/**
 * Parses the server address into the host/port. Handles both IPv6 and IPv4
 * addresses and Unix sockets
 *
 * @param string $server The server address string.
 * @return array Array containing host, port
 */
	protected function _parseServerString($server) {
		if ($server[0] === 'u') {
			return array($server, 0);
		}
		if (substr($server, 0, 1) === '[') {
			$position = strpos($server, ']:');
			if ($position !== false) {
				$position++;
			}
		} else {
			$position = strpos($server, ':');
		}
		$port = 11211;
		$host = $server;
		if ($position !== false) {
			$host = substr($server, 0, $position);
			$port = substr($server, $position + 1);
		}
		return array($host, $port);
	}

/**
 * Write data for key into cache. When using memcache as your cache engine
 * remember that the Memcached pecl extension does not support cache expiry times greater
 * than 30 days in the future. Any duration greater than 30 days will be treated as never expiring.
 *
 * @param string $key Identifier for the data
 * @param mixed $value Data to be cached
 * @param integer $duration How long to cache the data, in seconds
 * @return boolean True if the data was successfully cached, false on failure
 * @see http://php.net/manual/en/memcache.set.php
 */
	public function write($key, $value, $duration) {
		$result = $this->_Memcached->set($key, $value,$duration);		
		return $result;
	}
	
	public function getResultCode(){
	    return $this->_Memcached->getResultCode();
	}

/**
 * Read a key from the cache
 *
 * @param string $key Identifier for the data
 * @return mixed The cached data, or false if the data doesn't exist, has expired, or if there was an error fetching it
 */
	public function read($key) {
		return $this->_Memcached->get($key);
	}

/**
 * Increments the value of an integer cached key
 *
 * @param string $key Identifier for the data
 * @param integer $offset How much to increment
 * @return New incremented value, false otherwise
 * @throws CacheException when you try to increment with compress = true
 */
	public function increment($key, $offset = 1) {
		return $this->_Memcached->increment($key, $offset);
	}

/**
 * Decrements the value of an integer cached key
 *
 * @param string $key Identifier for the data
 * @param integer $offset How much to subtract
 * @return New decremented value, false otherwise
 * @throws CacheException when you try to decrement with compress = true
 */
	public function decrement($key, $offset = 1) {
		return $this->_Memcached->decrement($key, $offset);
	}

/**
 * Delete a key from the cache
 *
 * @param string $key Identifier for the data
 * @return boolean True if the value was successfully deleted, false if it didn't exist or couldn't be removed
 */
	public function delete($key) {
		return $this->_Memcached->delete($key);
	}

/**
 * Delete all keys from the cache
 *
 * @param boolean $check
 * @return boolean True if the cache was successfully cleared, false otherwise
 */
	public function clear($check) {
		if ($check) {
			return true;
		}
		foreach ($this->_Memcached->getExtendedStats('slabs') as $slabs) {
			foreach (array_keys($slabs) as $slabId) {
				if (!is_numeric($slabId)) {
					continue;
				}

				foreach ($this->_Memcached->getExtendedStats('cachedump', $slabId) as $stats) {
					if (!is_array($stats)) {
						continue;
					}
					foreach (array_keys($stats) as $key) {
						if (strpos($key, $this->settings['prefix']) === 0) {
							$this->_Memcached->delete($key);
						}
					}
				}
			}
		}
		return true;
	}

/**
 * Connects to a server in connection pool
 *
 * @param string $host host ip address or name
 * @param integer $port Server port
 * @return boolean True if memcache server was connected
 */
	public function connect($host, $port = 11211) {
		if ($this->_Memcached->getServerStatus($host, $port) === 0) {
			if ($this->_Memcached->connect($host, $port)) {
				return true;
			}
			return false;
		}
		return true;
	}

/**
 * Returns the `group value` for each of the configured groups
 * If the group initial value was not found, then it initializes
 * the group accordingly.
 *
 * @return array
 */
	public function groups() {
		if (empty($this->_compiledGroupNames)) {
			foreach ($this->settings['groups'] as $group) {
				$this->_compiledGroupNames[] = $this->settings['prefix'] . $group;
			}
		}

		$groups = $this->_Memcached->get($this->_compiledGroupNames);
		if (count($groups) !== count($this->settings['groups'])) {
			foreach ($this->_compiledGroupNames as $group) {
				if (!isset($groups[$group])) {
					$this->_Memcached->set($group, 1, false, 0);
					$groups[$group] = 1;
				}
			}
			ksort($groups);
		}

		$result = array();
		$groups = array_values($groups);
		foreach ($this->settings['groups'] as $i => $group) {
			$result[] = $group . $groups[$i];
		}

		return $result;
	}

/**
 * Increments the group value to simulate deletion of all keys under a group
 * old values will remain in storage until they expire.
 *
 * @return boolean success
 */
	public function clearGroup($group) {
		return (bool)$this->_Memcached->increment($this->settings['prefix'] . $group);
	}
}
